关联容器map实例

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/*编译： g++ -o map map.cpp */
#include<map>
#include<cstring>
#include<iostream>
typedef std::map<int, std::string> UDT_MAP_INT_CSTRING;
UDT_MAP_INT_CSTRING enumMap;

int main()
{
    /*数组方式插值：如果元素是类对象，则开销比较大*/
    /*它可以覆盖以前该关键字对应的值*/
    enumMap[1] = "One";
    enumMap[1] = "Two";//key: 1 value: Two
    std::map<int, std::string>::iterator it;
    for(it=enumMap.begin(); it!=enumMap.end(); ++it)
        std::cout<<"key: "<<it->first <<" value: "<<it->second<<std::endl;
    /*知道键，获取它的值*/
    std::string str_handle = enumMap[1];
    std::cout<<"str_handle "<<str_handle <<std::endl;

    /*第一、二种插值方式*/
    /*缺点：即当map中有这个关键字时，insert操作是插入数据不了的*/
    enumMap.insert(std::pair<int, std::string>(2, "student_one")); 
    enumMap.insert(std::pair<int, std::string>(2, "student_two")); 
    /* it_key: 2 it_value: student_one */
    std::map<int, std::string>::iterator it_it;
    for(it_it=enumMap.begin(); it_it!=enumMap.end(); ++it_it)
        std::cout<<"it_key: "<<it_it->first <<" it_value: "<<it_it->second<<std::endl;

    enumMap.insert(std::map<int, std::string>::value_type(3, "student_three"));
    enumMap.insert(std::map<int, std::string>::value_type(3, "student_four"));
    std::map<int, std::string>::iterator it_two;
    for(it_two=enumMap.begin(); it_two!=enumMap.end(); ++it_two)
        std::cout<<"two_key: "<<it_two->first <<" two_value: "<<it_two->second<<std::endl;
    return 0;
}
/***********************************
结果：
    key: 1 value: Two
    str_handle Two
    it_key: 1 it_value: Two
    it_key: 2 it_value: student_one
    two_key: 1 two_value: Two
    two_key: 2 two_value: student_one
    two_key: 3 two_value: student_three
***********************************/